the horn blows but the engine won't start. What could be the issue on 2007 Buick LaCrosse

I checked the electronic throttle control fuse and it is good

Asked by for the 2007 Buick LaCrosse
does the car crank over?
The car did not crank over. There was only a click then the horn would blow. Hearing the click made me think the starter might be bad. Needing the car, I called a mechanic and found the problem was the battery! Paid a hefty wrecker bill to have the car towed to the garage to replace the battery! Thanks for the response.